Verizon Wireless subscribers’ unfettered access to unlimited 4G LTE high-speed mobile Internet may soon come to an end. The wireless carrier plans to expand its practice called network optimization, a process where mobile data connections may be throttled, or temporarily slowed down, during times when the Verizon network is being heavily used.

According to Droid Life, the Verizon Communications Inc. (NYSE:VZ) subsidiary plans to expand the throttling initiative, which previously only affected unlimited data plan users on Verizon’s older 3G network. Starting October 1, customers on the Verizon Wireless 4G LTE network with unlimited data plans will see the effects of its network optimization throttling practices.

But according to Verizon there are certain criteria that need to be met in order for the temporary slow downs to occur. Namely, being one of the top five percent of data users, having an unlimited data plan, have already fulfilled the minimum term of a contract plan and using mobile data in an area during high demand. In contrast, carriers such as T-Mobile (NYSE:TMUS) and AT&T (NYSE:T) currently relegate “unlimited” data plans to slower speeds for the rest of the month if exceeding a pre-determined usage limit.

Verizon classifies the top five percent of its users as those that use at least 4.7 gigabytes of data.

“As of March 2014, the top 5% of data users were using 4.7 GB or more of data each month,” Verizon’s frequently asked questions page reads.

In order to mitigate problems faced when Verizon rolls outs its throttling procedures in October, the wireless carrier offers a few suggestions, such as using Wi-Fi as much as possible, monitoring data usage more closely, or switching to a metered, usage-based plans.

Starting August 1, Verizon is expected to notify subscribers of the change with the following message:

“Wireless strives to provide its customers with the best wireless experience when using our network. In 2011, Verizon Wireless launched Network Optimization, which slows the data speeds of its unlimited data subscribers with 3G devices who are in the top 5% of data users when they connect to a cell site experiencing high demand. Effective October 1, Verizon Wireless will expand its existing Network Optimization policy to include its unlimited data subscribers using 4G LTE devices who have fulfilled their minimum contract term. Based on your plan and recent data usage, one or more lines on your account may experience a reduction in data speeds when connected to a cell site experiencing high demand. Customers on MORE Everything or other usage-based data plans are not subject to Network Optimization. For more information about our Network Optimization, please refer to www.verizonwireless.com/networkoptimization.”

Overall, Verizon appears to have found success in switching its unlimited data users to usage-based plans. While a report by Consumer Intelligence Research Partners, or CIRP, claims that 22 percent of Verizon’s users are unlimited data plans, the wireless carrier claims that the figures are actually much lower than the study suggests.